1 /* 2 * linux/arch/arm/mach-sa1100/clock.c 3 */ 4 #include <linux/module.h> 5 #include <linux/kernel.h> 6 #include <linux/device.h> 7 #include <linux/list.h> 8 #include <linux/errno.h> 9 #include <linux/err.h> 10 #include <linux/string.h> 11 #include <linux/clk.h> 12 #include <linux/spinlock.h> 13 #include <linux/mutex.h> 14 #include <linux/io.h> 15 #include <linux/clkdev.h> 16 17 #include <mach/hardware.h> 18 19 struct clkops { 20 void (*enable)(struct clk *); 21 void (*disable)(struct clk *); 22 }; 23 24 struct clk { 25 const struct clkops *ops; 26 unsigned int enabled; 27 }; 28 29 #define DEFINE_CLK(_name, _ops) \ 30 struct clk clk_##_name = { \ 31 .ops = _ops, \ 32 } 33 34 static DEFINE_SPINLOCK(clocks_lock); 35 36 /* Dummy clk routine to build generic kernel parts that may be using them */ 37 unsigned long clk_get_rate(struct clk *clk) 38 { 39 return 0; 40 } 41 EXPORT_SYMBOL(clk_get_rate); 42 43 static void clk_gpio27_enable(struct clk *clk) 44 { 45 /* 46 * First, set up the 3.6864MHz clock on GPIO 27 for the SA-1111: 47 * (SA-1110 Developer's Manual, section 9.1.2.1) 48 */ 49 GAFR |= GPIO_32_768kHz; 50 GPDR |= GPIO_32_768kHz; 51 TUCR = TUCR_3_6864MHz; 52 } 53 54 static void clk_gpio27_disable(struct clk *clk) 55 { 56 TUCR = 0; 57 GPDR &= ~GPIO_32_768kHz; 58 GAFR &= ~GPIO_32_768kHz; 59 } 60 61 int clk_enable(struct clk *clk) 62 { 63 unsigned long flags; 64 65 if (clk) { 66 spin_lock_irqsave(&clocks_lock, flags); 67 if (clk->enabled++ == 0) 68 clk->ops->enable(clk); 69 spin_unlock_irqrestore(&clocks_lock, flags); 70 } 71 72 return 0; 73 } 74 EXPORT_SYMBOL(clk_enable); 75 76 void clk_disable(struct clk *clk) 77 { 78 unsigned long flags; 79 80 if (clk) { 81 WARN_ON(clk->enabled == 0); 82 spin_lock_irqsave(&clocks_lock, flags); 83 if (--clk->enabled == 0) 84 clk->ops->disable(clk); 85 spin_unlock_irqrestore(&clocks_lock, flags); 86 } 87 } 88 EXPORT_SYMBOL(clk_disable); 89 90 const struct clkops clk_gpio27_ops = { 91 .enable = clk_gpio27_enable, 92 .disable = clk_gpio27_disable, 93 }; 94 95 static DEFINE_CLK(gpio27, &clk_gpio27_ops); 96 97 static struct clk_lookup sa11xx_clkregs[] = { 98 CLKDEV_INIT("sa1111.0", NULL, &clk_gpio27), 99 CLKDEV_INIT("sa1100-rtc", NULL, NULL), 100 }; 101 102 static int __init sa11xx_clk_init(void) 103 { 104 clkdev_add_table(sa11xx_clkregs, ARRAY_SIZE(sa11xx_clkregs)); 105 return 0; 106 } 107 core_initcall(sa11xx_clk_init); 108